Treatment of White South Sea Pearl

[Sutrisno]

Wow, these are such great infos! So about fw pearls going chalky, where then can i get a properly treated fw pearls that don't go chalky? I really love their colour but i myself have had a few that done that and sort of got me thinking it was one reason why fe pearls are so cheap compared to ss. But it would be wondrous to get a hold on a putple fw strand that doesn't turn chalky!

 

[Marianne]

If the pearls are naturally purple (not dyed), then they should not turn chalky as they have not been bleached

 

[Adeline Leigh]

I'd like to see an example of a chalky pearl that has gone off. Anyone has one?

 

[pearlescence]

Maeshori is analagous to buffing your nails with a wax or oil with a buffing pad and brisk rubbing rather than putting coloured nail polish on them....?

 

[Caitlin]

Maybe, but bleaching is also included in maeshori more often than not. I think the corn cob polish is the equivalent to buffing your nails with wax more than the heating and treating of maeshori- which seems to vary from plant to plant and perhaps within a plant, if different types of maeshori are performed......?

Maeshori- a big Pearl Mystery........

 

[pattye]

Wow, these are such great infos! So about fw pearls going chalky, where then can i get a properly treated fw pearls that don't go chalky? I really love their colour but i myself have had a few that done that and sort of got me thinking it was one reason why fe pearls are so cheap compared to ss. But it would be wondrous to get a hold on a putple fw strand that doesn't turn chalky!

Sorry Marianne, I didn't see your earlier reply. Naturally colored cultured freshwater pearls, purple, pink, peach, and such aren't bleached so they shouldn't get chalky. It's the white pearls that are sometimes at risk. Personally, I've had some dull spots on otherwise lovely keshi pearls, that were from over-bleaching. I will see if I can find them and take a photo. (The other problem with these pearls is that they have minute cracks on one side from being too tightly clamped when they were drilled.)

 

[KarinK]

I finally got around to revisiting a thread about maeshori that I started about a year ago. I find Jeremy's post (#4, https://www.pearl-guide.com/forum/showthread.php?t=4788&page=1&highlight=) very informative and relevant to the pretty much identical description going on here.

Quoting Jeremy's post of August 26, 2011:

Maeshori has a lot of meanings now. It is a Japanese word that literally means before (mae) treatment (shori). It is a treatment used on all akoya, freshwater and some South Sea. Maeshori treatments vary from factory to factory, but Karin is more or less correct in what it does. It tightens the nacre and pulls moisture out, which will enhance the luster but also make the nacre more brittle. In freshwater, pearls that have been over-treated will turn chalky in short order.

Maeshori with South Sea pearls is a very common treatment in Japan. It makes the pearls whiter, brighter, and more salable. It isn't a necessary treatment, in my opinion. Joseph Taylor from Atlas does sell his treated, and his pearls are beautiful. Other producers, like Kakuda growing in Indonesia, universally treat their South Sea, but they also disclose the maeshori.

To me this description of what maeshori does to the pearl confirms my oppinion that it is to be considered a "treatment".

- Karin

 

[R&B]

This whole yarn highlights that due to the various treatments carried out, unfortunately many people will not be aware just what natural high quality nacre is.

Sorry for repeating myself but, the pearls are harvested, needed in salt to remove dried mucus and such then rinsed in fresh water.

When dry, they can be sized and graded. At this point what you see and judge is the pearl in its natural splendor or lack of (hence the system called grading).

Soaking in oils, tumbling in walnut or corn husks or meashori is "tampering with the evidence" or "stretching the truth". However, if, in a real fancy way you tell the person you did it to bring out the true inner beauty of the pearl that mankind would have been denied the opportunity to see had you not done so, well good luck to you.

Treatment, puts our industry in line with the used car trade.

I mean no offence, but please understand that as a pearl farmer, when people "treat" pearls to change their grade, I'm offended.

 

[pearlescence]

Not sure I agree with the analogy there about used car salesmen...is it not reasonable to clean and polish a car in order to sell it...that is a different order of treatment to a cut and shut or other various selling dodges intending to conceal mechanical defects etc.
While these are processes I would not call them tampering - they are not doing more than polishing a car or brushing one's hair ..they are enhancing what is already there rather than adding to it artificially....?

 

[jshepherd]

I'm not sure I agree either and Australia's largest producer (Paspaley) would also disagree:
https://www.pearl-guide.com/forum/showthread.php?t=1822&p=17568#post17568

The large majority of pearls grown in Australia have gone through maeshori prior to reaching the consumer, as most of the pearls go through Japan.

 

[CLICLASP]

Thank you Jeremy for reminding us that fantastic post.

 

[Caitlin]

So maeshori includes tumbling polishes? Or do the Paspaleys do other types of maeshori?

 

[jshepherd]

No. One would never polish pearls before treating them. Polishing would not be a pre-treatment, it would be done post-treatment.
Edit: Unless it was done to prepare the pearls for auction. After the pearls are sold at auction, (to almost exclusively Japanese processors) they will go through maeshori and then again polishing.

 

[Caitlin]

That is what I thought. So,the pearls Paspaley keeps are just tumbled, but they ones that go to Japan go through Maeshori? I am just getting more confused, because when I went to the other thread, they showed the Paspaley Pearls being tumbled. What did I miss?

 

[jshepherd]

You didn't miss anything. The link was in response to Rusty's post.

Soaking in oils, tumbling in walnut or corn husks or meashori is "tampering with the evidence" or "stretching the truth". However, if, in a real fancy way you tell the person you did it to bring out the true inner beauty of the pearl that mankind would have been denied the opportunity to see had you not done so, well good luck to you.

Treatment, puts our industry in line with the used car trade.

I mean no offence, but please understand that as a pearl farmer, when people "treat" pearls to change their grade, I'm offended.

It is easy to disparage what other people do, but my point is that almost always something is being done. Paspaley is polishing the pearls with oil-infused walnut shell in that photo and calling it "washing." Even the producers who do absolutely nothing to their pearls know full well that when they sell them (hama-age lots), nearly all of them are going to go through some sort of processing if they go through Japan. Even the finest pearls will at least go through some sort of polishing.

 

[lisa c]

Besides, the nature of what's doing the polishing matters. Crushed walnut shells are really rather benign compared with something like a gem-slurry or the like. Crushed nut shells are used in skin scrubs/exfolliants. So, how could it be considered as anything other than a slight buffer? Do I have that right?

 

[jshepherd]

It still "brings out the inner beauty of the pearl." When you exfoliate, you are doing the same thing in a way. But pearl polishing in this fashion is not meant to remove and layers.

IMHO, after a strand has been drilled and worked, it should definitely be polished. The pearls have been stuck to a stick pad, have pearl dust stuck in the microscopic crevices, and have been handled extensively. They don't need to go on a polishing wheel, but corn or walnut will make them shine.

 

[lisa c]

Thanks for sharing info so patiently.

That's about what I figured. If it's safe for human skin it wouldn't do anything much to a pearl's surface, aside from cleaning and I like the analogy to buffing one's nails.

 

[Lagoon Island Pearls]

Technically, anything that prepares a pearl for market are post harvest "treatments". Salt slurry scrubbing, drying and oiling included.

In all of my naturals, blisters and cultured pearls, drying is where I draw the line. Table salt etches the surface of pearls and contains chlorine... which is an oxidizer and sodium... which is a metal.

Sea salt contains even more elements:

Element Relative concentration (by mass) [%]
Chloride (Cl-) 55.03
Sodium (Na+) 30.59
Sulfate (SO42-) 7.68
Magnesium (Mg2+) 3.68
Calcium (Ca2+) 1.18
Potassium (K+) 1.11
Bicarbonate (HCO3-) 0.41
Bromide (Br-) 0.19
Borate (BO33-) 0.08
Strontium (Sr2+) 0.04
Miscellaneous constituents 0.01

Ana has asked me about my post harvest treatments in the past, presumably because any foreign agents applied to pearls will skew the spectrum analysis of SEM. Protein (especially once dried) sticks to aragonite like poop to a wool blanket. She often notes, it's very difficult to break a shell or pearl to obtain a clean, entire crystal.

Merely because most cultured pearls will never see the inside of a lab does not mean they are exempt from correct terminology. There are way to many abused terms in pearling and we ought not perpetuate them needlessly.

I'm with R&B on this one. IMHO, cultured pearls that are never intended to be scientifically analyzed and treated in a wet slurry of salt by non-mechanical means (ie) manually can be deemed as cleaned and "untreated" or minimally treated. Pearls treated with any other agent or thermal control without disclosure are cheating the grade system.

 

[jshepherd]

Opinion is just that and why we are here. We have many that do have the more purist view on these things and they can be debated, but nothing is going to change within the industry, especially given the amount of secrecy involved in everything from maeshori, bleaching and even in some cases polishing. Within the industry, from many producers, wholesaler, retailers, to even a lot of consumers, many of our opinions would be viewed as the fringe.

From the time only natural pearls ruled the world, treatments and processing were a part of business and were not often discussed. Pearls were bleached in bottles of water left in the sun. Natural pearls were often, and still are, sold with the most invasive treatment of all (peeling), and yet it is not routinely disclosed.

I submit that if anyone posting in this thread was a processor in Japan, they would follow the same protocol that is their industry standard.